We usually stay at US and spend of couple days at WDW since we've discovered how nice this resort is.
We usually reserve a car at PBH and drive over. Do not have to pay for parking, just park back in Alamo area. It's only about 15 min away and you get more flexibility than trying to do Mears. And depending on how many is in your party, it will probably be cheaper. Believe me, its better to reserve a car for a day or two and not have revolve your precious vacation time around a shuttle schedule. We are going to do AK and MGM one day and DQ and House of Blues another evening during mid-week. We have already reserved our car for two days at the AAA rate. I haven't check yet to see if I can get a better rate with my fun card.